1. Field of the Invention
The present invention relates to the field of aircraft flight control and, more particularly, emergency flight control.
2. Related Art
The attacks on United States soil by terrorist forces on Sep. 11, 2001 using domestic aircraft indicate that present airport security is inadequate and may never be adequate to prevent another hijacking. Airline security may be enhanced by a mechanism that deters would-be hijackers because attempted hijacking would become futile. Such a mechanism is not only applicable for domestic non-military aircraft in the United States, but also may deter terrorists from attempting a hijacking anywhere in the world. Early weapon detection and other prevention techniques may prevent hijackers from boarding an aircraft, but once the aircraft is airborne with weapons aboard, all the prevention systems and techniques are ineffective. Consequently, detection of carried-on weapons and other prevention techniques may never be capable of preventing the forced takeover of an aircraft.
While detecting the presence of some weapons carried by would-be airline passengers is possible, weapons can be made from not only disassembled components being reassembled, but also from parts of the interior of the aircraft. Airport security metal detectors and other screening methods are not capable of entirely detecting such weapons. Further, once a terrorist has taken over the aircraft, all detection systems then become questioned in their accuracy and detection methods.
The airport detection methods and apparatus, while improved, are subject to the varying skill level and attentiveness of the security attendants at any particular airport. Multiple passes through such detection systems indicate inherent flaws in accurately detecting weapons. For instance, a first pass through a metal detector may indicate that a person has sufficient metal content to trigger a positive no-go signal on a go/no-go signal standard, which is usually represented by an audible tone alerting the attendant to a potential problem. The person then removes his or her watch, which may or may not be the source of the positive trigger, and then re-passes through the metal detector not setting-off the go/no-go signal although the metal detection signal strength falls just short of a pre-set trigger level. Further, each metal detector may be calibrated to a slightly different scale, thereby allowing some higher metal content to pass through some detectors while not passing through others. Even considering a perfect metal detector scheme, such machines may not be capable of picking up plastic, ceramic, or other weapons and sub-assemblies. Like the metal detection systems, carry-on baggage detectors are subject to human skill and alertness. Human errors in detecting weapons either on-passenger or in carry-on luggage have the potential of allowing dangerous weapons in the passenger compartment of aircraft.
While the hijacking of commercial aircraft requires immediate attention and correction, aircraft safety is also affected by incapacitated flight crews. For example, pilots may suffer sudden health problems. For instance, a pilot may suffer a heart attack in-flight and, unbeknownst to other flight crew, if any other crew exists, the aircraft may veer off-course or dive from present altitude. While autopilot, if available in the present system, may be engaged in such a situation, the autopilot may require periodic inputs from the pilot. Also, autopilot may not include autoland sequencing, which may require additional inputs from the pilot or co-pilot, if any. If a pilot suffers a heart attack, a seizure, or another incapacitating event, the pilot may not be able to respond to the required periodic or queried inputs. A mechanism that allows external, i.e. non-piloted input, functional control of the aircraft thus can increase the safety of the passengers and crew of the aircraft, and can protect against destruction of property.
Another situation arises if the aircraft automatic and/or manual controls break or malfunction. The pilot may not have the ability to correctly fly the aircraft, creating a potential for devastation. Although many aircraft are “fly-by-wire” and incorporate both redundant mechanical and electrical systems to protect against failure, these systems still require wiring systems and interconnects that may prevent the pilot or other persons from controlling the aircraft. A mechanism for externally controlling the aircraft, when pilot intervention is severed provides protection in instances as described above.